mtex2MML

This is a Bison grammar to convert TeX math into MathML. It can be used as a standalone program or as a static library. It is written in standard C99. It's been tested on OS X, Ubuntu, and Windows.

The goal of this project is to implement as much of AMS-TeX math as possible.

This code is a fork of the itex2MML project, originally written by Jacques Distler and Paul Gartside. It has vastly more support for AMS-TeX math than the original, with a much larger test suite.

Why MathML?!

It's true, MathML is not well supported in browsers. (Kudos to the Firefox team for sticking with it!)

However, you can consider MathML as an intermediate format onto greater things, like conversion to SVG via mathematical.

What's supported?

Please refer to SUPPORTED.md for more information on what this lib can do. Right now it has a ~93% compatibility with everything MathJax can do.

The most obvious gap in this library is the inability to define new commands (via \mathop, \def, \mathchoice, etc.). Everything else in standard TeX math should be fine.

Usage

By default, inline equations are demarcated by $...$. Display equations are demarcated by $$...$$. You can change these to \(..\) and \[..\] respectively; see below for configuration.

You cannot nest equations; for example, $$...\text{foo $...$ bar}...$$ is not allowed.

Heuristics

Since $ signs appear quite often in plaintext, a basic heuristic is applied to calculate whether $ should be interpreted as math or not:

Basic heuristic is: opening $ can't be followed by whitespace, closing $ can't be followed by a digit or preceded by whitespace." -- @jgm, http://bit.ly/1HVtemx

Of course, if you type \$, no math is applied as the $ is considered skipped.

As a library

Both a static and dynamic library are created as part of the cmake build process. Include one of them during the compilation of your program.

Methods available

The library exposes the following methods:

• char * mtex2MML_parse(const char * str, unsigned long strlen, const int options): Converts a single TeX equation in str to MathML. Returns just the MathML equation, as a string.

• char * mtex2MML_global_parse(const char * str, unsigned long strlen, const int options, int global_start): The same as mtex2MML_parse, but allows you to provide a starting integer for equation numbering. Returns just the MathML equation, as a string.

• int mtex2MML_filter(const char * str, unsigned long strlen, const int options): Given a string with a mix of TeX math and non-math elements, this returns a single string containing just the converted math elements. Equations are automatically numbered. Returns a status indicating success (0) or failure. You must access the resulting string with mtex2MML_output.

• int mtex2MML_text_filter(const char * str, unsigned long strlen, const int options): Given a string with a mix of TeX math and non-math elements, this converts all the math and leaves the rest of the string unmodified. Equations are automatically numbered. Returns a status indicating success (0) or failure. You must access the resulting string with mtex2MML_output. HTML within a math equation are normalized (eg. < becomes <).

• int mtex2MML_strict_filter(const char * str, unsigned long strlen, const int options): Given a string with a mix of TeX math and non-math elements, this converts all the math and leaves the rest of the string unmodified. Equations are automatically numbered. Returns a status indicating success (0) or failure. You must access the resulting string with mtex2MML_output. HTML tags are removed completely.

The options argument determines which types of delimiters are to be used:

• MTEX2MML_DELIMITER_DEFAULT is the default, using $..$ for inline and $$..$$ for display.
• MTEX2MML_DELIMITER_DOLLAR uses single dollar signs: $..$ for inline.
• MTEX2MML_DELIMITER_DOUBLE uses double dollar signs: $$..$$ for display.
• MTEX2MML_DELIMITER_PARENS uses parenthesis: \(..\) for inline.
• MTEX2MML_DELIMITER_BRACKETS uses brackets: \[..\] for display.
• MTEX2MML_DELIMITER_ENVIRONMENTS supports bare \\begin..\\end environments.

The tests/basic.c and the tests/delimiters.c suites provides a demonstrate of how these methods can be used.

As a command

Like any good Unix program, the mtex2MML binary operates on pipes. That is to say, it works like this:

echo '\sin y' | mtex2MML --inline > math.txt

Use mtex2MML -h to get documentation on the options.

Error handling

A 0 status indicates a success, while anything else indicates a failure, as per the Bison documentation. If a token cannot be parsed, or if the tokenization is nested too deep, the library will bail with a non-zero status code. An error message is also printed to STDERR.

The tests/maliciousness.c suite has a demonstration on how to perform error handling.

Building

To build mtex2MML, you need:

• CMake (at least version 2.8.7)
• Bison
• Flex
• Python3 (just for the tests)

OS X (brew or macports), Ubuntu and Arch Linux

To fetch dependencies, build, and run the library, call:

script/bootstrap
cd build
cmake ..
make

Windows

With Chocolatey, you can run:

choco install cmake winflexbison python3

Then, with Powershell, simply run build.ps1.

Testing

Assuming you've built the programs, to run the test suite:

cd build
ctest -V

mtex2MML has a test suite that mimics the one found in MathJax, with a few exceptions:

• Files marked as .xtex have features that are not implemented, but probably should be in the future.
• Files marked as .no_tex have features that probably won't be implemented.

During the test run, the suite will list the percentage of features that still need coverage.

Installing

To install the mtex2MML binary, you can run:

cd build
make install

Contributing

Found a bug or want to request a feature? Great! Check out CONTRIBUTING.md for more information!

License

As with the original version(s), this is Open Source software, released under a triple license: GPL, MPL, and LGPL.